Mitral valve regurgitation is a disorder in which the mitral valve does not close properly. During systole, a healthy mitral valve prevents oxygenated blood from flowing back (regurgitating) from the left ventricle to the left atrium. Regurgitation caused by a defective mitral valve reduces cardiac output, increasing the risk of progressive heart failure. Treatments for mitral valve regurgitation include valve replacement and strengthening the valve annulus by implanting a mechanical support ring or other structure (generally called valve annuloplasty).
The chordae tendineae are commonly classified according to their insertion sites on the mitral cusps. The first-order (also called primary or marginal) chordae insert on the cusp free edges, the second-order (also called “strut”) chordae insert on the ventricular surface of the cusps, usually near the junction between the rough and smooth zones, and the third-order (also called tertiary or basal) chordae originate directly from the trabeculae cameae of the left ventricular wall, and attach to the cusps near the annulus of the mitral valve.
US Patent Application Publication 2005/0010287 to Macoviak et al., which is incorporated herein by reference, describes techniques for supplementing, repairing, or replacing a native heart valve. The techniques employ an implant that is adapted to extend adjacent a valve annulus. The implant includes a mobile neoleaflet element that occupies the space of at least a portion of one native valve leaflet. The implant mimics the one-way valve function of a native leaflet, to resist or prevent retrograde flow. The implant restores normal coaptation of the leaflets to resist retrograde flow, thereby resisting eversion and/or prolaspe, which, in turn, reduces regurgitation.
US Patent Application Publication 2004/0193191 to Starksen et al., which is incorporated herein by reference, describes methods for treating a cardiac valve annulus, comprising contacting an anchor delivery device with the valve annulus and releasing a plurality of coupled anchors from the anchor delivery device to secure the anchors to the annulus. Anchors, which in some embodiments are super-elastic or shape memory self-securing anchors, are then drawn together to tighten the annulus. The publication also describes devices including an elongate catheter having a housing at or near the distal end for releasably housing a plurality of coupled anchors. The housing may be flexible, may conform to a valve annulus, and in some embodiments may be coupled with an expandable member to enhance contact of the housing with annular tissue. In one embodiment, self-securing anchors lie approximately flat within the delivery device housing, allowing anchors with relatively large deployed shapes to be housed in and deployed from a relatively narrow delivery device.
US Patent Application Publication 2004/0148020 to Vidlund et al., which is incorporated herein by reference, describes techniques for improving the function of a valve (e.g., a mitral valve) by positioning an implantable device outside and adjacent the heart wall such that the device alters the shape of the heart wall acting on the valve. The implantable device may alter the shape of the heart wall acting on the valve by applying an inward force and/or by circumferential shortening (cinching). The shape change of the heart wall acting on the valve is sufficient to change the function of the valve, and may increase coaptation of the leaflets, for example, to reduce regurgitation.
US Patent Application Publication 2004/0148019 to Vidlund et al., which is incorporated herein by reference, describes techniques for improving the function of a valve (e.g., a mitral valve) by positioning a spacing filling device outside and adjacent the heart wall such that the device applies an inward force against the heart wall acting on the valve. A substantially equal and opposite force may be provided by securing the device to the heart wall, and/or a substantially equal and opposite outward force may be applied against anatomical structure outside the heart wall. The inward force is sufficient to change the function of the valve, and may increase coaptation of the leaflets, for example. The space filling device may be implanted by a surgical approach, a transthoracic approach, or a transluminal approach, for example. The space filling portion may be delivered utilizing a delivery catheter navigated via the selected approach, and the space filling portion may be expandable between a smaller delivery configuration and a larger deployed configuration.
US Patent Application Publication 2004/0138745 to Macoviak et al., which is incorporated herein by reference, describes medical devices for improving heart valve function, including leaflet retainers, a neo-annulus, neo-leaflet, and a framework.
US Patent Application Publication 2004/012983 to Mortier et al., which is incorporated herein by reference, describes a device for heart valve repair including at least one tension member having a first end and second end. A basal anchor is disposed at the first end of the tension member and a secondary anchor at the second end. The publication describes a method including the steps of anchoring the basal anchor proximate a heart valve and anchoring the secondary anchor at a location spaced from the valve such that the chamber geometry is altered to reduce heart wall tension and/or stress on the valve leaflets.
U.S. Pat. No. 6,629,534 and US Patent Application Publication 2004/0039442 to St. Goar et al., which are incorporated herein by reference, describe techniques for performing endovascular repair of atrioventricular and other cardiac valves in the heart. Regurgitation of an atrioventricular valve, particularly a mitral valve, is repaired by modifying a tissue structure selected from the valve leaflets, the valve annulus, the valve chordae, and the papillary muscles. These structures are modified by suturing, stapling, snaring, or shortening, using interventional tools which are introduced to a heart chamber.
US Patent Application Publication 2003/019974 to Lee et al., which is incorporated herein by reference, describes an annuloplasty system for repairing a heart valve, comprising a surgical implant including a member having first and second end portions. The implant member further is configured and/or adapted to form a partial ring along a portion of one of the valve annulae of a patient's heart such as the mitral or tricuspid valve annulus. The implant member is axially elastic such that it can axially expand and contract and includes first and second anchors extending from the end portions of the implant member. The anchors are adapted to anchor the implant in tissue such as the mitral or tricuspid valve annulus. The system is described as facilitating tissue plication (e.g., of the posterior annulus of the mitral valve or the annulus of the tricuspid valve) and reinforcement of a valve annulus.
US Patent Application Publication 2003/0191528 to Quijano et al., which is incorporated herein by reference, describes an expandable annular ring for implantation in a valvular annulus and its percutaneous use. The ring comprises a plurality of stenting elements made of a first shape-memory material having a first shape-transition temperature, wherein the first shape-memory material expands to a preshape when the first shape-memory material is heated to above the first shape-transition temperature; and a plurality of anchoring elements made of a second shape-memory material having a second shape-transition temperature that is higher than the first shape-transition temperature, wherein the second shape-memory material expands to the second preshape when the second shape-memory material is heated to above the second shape-transition temperature.
US Patent Application Publications 2004/0260393 to Rahdert et al. and 2004/0127982 to Machold et al., which are incorporated herein by reference, describe techniques using an implant that is sized and configured to attach in, on, or near the annulus of a dysfunctional heart valve. In use, the implant extends either across the minor axis of the annulus, or across the major axis of the annulus, or both. The implant is described as restoring to the heart valve annulus and leaflets a more functional anatomic shape and tension. The more functional anatomic shape and tension are conducive to coaptation of the leaflets, which, in turn, reduces retrograde flow or regurgitation.
US Patent Application Publication 2004/0260394 to Douk et al., which is incorporated herein by reference, describes a cardiac valve annulus compressor comprising a generally cylindrical main body having plain and barbed ends and an actuator portion. Barbs disposed on the barbed end are engageable with the valve annulus. The length of the circumference of the barbed end is responsive to movement of the actuator portion. The annulus compressor can be delivered percutaneously or surgically.
US Patent Application Publication 2004/0236419 to Milo, which is incorporated herein by reference, describes methods for reconfiguring an atrioventricular heart valve that use systems comprising a partial or complete annuloplasty rings proportioned to reconfigure a heart valve that has become in some way incompetent, a pair of trigonal sutures or implantable anchors, and a plurality of staples which may have pairs of legs that are sized and shaped for association with the ring at spaced locations along its length. These systems are described as permitting relative axial movement between the staples and the ring, whereby a patient's heart valve can be reconfigured in a manner that does not deter subtle shifting of the native valve components. Shape-memory alloy material staples may have legs with free ends that interlock following implantation. Annuloplasty rings may be complete or partial and may be fenestrated. One alternative method routes a flexible wire, preferably of shape-memory material, through the bights of pre-implanted staples. Other alternative systems use linkers of shape-memory material having hooked ends to interengage with staples or other implanted supports which, following implantation, decrease in effective length and pull the staples or other supports toward one another so as to create desired curvature of the reconfigured valve. These linkers may be separate from the supports or may be integral with them and may have a variety of shapes and forms. Various of these systems may be implanted non-invasively using a delivery catheter.
US Patent Application Publication 2004/0243227 to Starksen et al., which is incorporated herein by reference, describes techniques for facilitating positioning of a cardiac valve annulus treatment device. The publication describes methods including advancing an anchor delivery device through vasculature of the patient to a location in the heart for treating the valve annulus, contacting the anchor delivery device with a length of the valve annulus, delivering a plurality of coupled anchors from the anchor delivery device to secure the anchors to the annulus, and drawing the anchors together to circumferentially tighten the valve annulus. Devices generally include an elongate catheter having at least one tensioning member and at least one tensioning actuator for deforming a distal portion of the catheter to help it conform to a valve annulus. The catheter device may be used to navigate a subannular space below a mitral valve to facilitate positioning of an anchor delivery device.
Odell J A et al., in an article entitled “Early Results of a Simplified Method of Mitral Valve Annuloplasty,” Circulation 92:150-154 (1995), which is incorporated herein by reference, studied the outcome of three different annuloplasty techniques: commissural annuloplasty, complete ring annuloplasty, and an unmeasured, posterior, partial ring annuloplasty. They concluded that postoperative valve function obtained by unmeasured posterior annuloplasty, as assessed by degree of regurgitation, transvalvular gradient, and valve area, was similar to that obtained by measured, complete ring annuloplasty and superior to that found in patients having commissural annuloplasty.
US Patent Application Publication 2003/0078465 to Pai et al., which is incorporated herein by reference, describes techniques for testing degenerative, congestive heart disease and related valvular dysfunction. Percutaneous and minimally invasive surgical tensioning structures are implantable within various major coronary blood-carrying conduit structures (arteries, veins and branching vessels), into or through myocardium, or into engagement with other anatomic structures that impact cardiac output to provide tensile support to the heart muscle wall which resists diastolic filling pressure while simultaneously providing a compressive force to the muscle wall to limit, compensate or provide therapeutic treatment for congestive heart failure and/or to reverse the remodeling that produces an enlarged heart. In some embodiments, the tensioning structures are used to apply tension to papillary muscles and/or chordae tendineae to reposition the valve leaflets to reduce/eliminate regurgitation, to limit the motion of the leaflets to improve/restore the function of cardiac valves; and to directly reposition the valve leaflets to prevent prolapse or other abnormalities of the leaflets and to prevent associated deficiencies.
US Patent Application Publication 2003/0018358 to Saadat, which is incorporated herein by reference, describes techniques for thermally and/or mechanically treating tissue, such as valvular structures, to reconfigure or shrink the tissue in a controlled manner. Mechanical clips are implanted over the leaflets of a valve, e.g., in the heart, either alone or after thermal treatment to cause the valve to close more tightly. The clips are delivered by a catheter and may be configured to traverse directly over the valve itself or to lie partially over the periphery of the valve to prevent obstruction of the valve. channel. Alternatively, individual anchors with a tensioning element, like a suture, are described as being useful for approximating the valves towards each other.
U.S. Pat. No. 6,626,899 to Houser et al., which is incorporated herein by reference, describes techniques for thermally and/or mechanically treating tissue, such as valvular structures, to reconfigure or shrink the tissue in a controlled manner. The apparatus comprises a catheter in communication with an end effector which induces a temperature rise in an annulus of tissue surrounding the leaflets of a valve or in the chordae tendineae sufficient to cause shrinkage, thereby causing the valves to close more tightly. Mechanical clips can also be implanted over the valve either alone or after the thermal treatment. The clips are delivered by a catheter and may be configured to traverse directly over the valve itself or to lie partially over the periphery of the valve to prevent obstruction of the valve channel.
US Patent Application Publication 2005/0222678 to Lashinski et al., which is incorporated herein by reference, describes methods and devices for applying pressure to an adjacent tissue structure, such as the annulus of the mitral valve. An adjustable implant is described with an elongate control line having a distal end connected to the implant and a proximal end spaced apart from the implant. The device enables post implantation adjustment, by accessing the proximal end of the control line and manipulating the control line to adjust the implant.
US Patent Application Publication 2005/0096740 to Langberg et al., which is incorporated herein by reference, describes a mitral annuloplasty and left ventricle restriction device adapted to be transvenously advanced and deployed within the coronary sinus and, in some embodiments, other coronary veins. The device places tension on adjacent structures, reducing the diameter and/or limiting expansion of the mitral annulus and/or limiting diastolic expansion of the left ventricle. These effects may be beneficial for patients with dilated cardiomyopathy.